Abstract

The time evolution of the Bragg peaks of photo-excited gold nanofilms is measured using transmission ultrafast electron diffraction (UED) with 3.0 MeV electron pulses and the corresponding structure evolution is calculated using two-temperature molecular dynamics (2T-MD). The good agreement obtained between the measured and calculated Bragg peaks, over the full experimental timescale, enables the lattice temperature effects and the structural changes to be disentangled for the first time. The agreement demonstrates that 2T-MD is a reliable method for solving the inverse problem of structure determination of laser irradiated metals in UED measurements.

Received 23 August 2013Accepted 25 November 2013Published online 17 December 2013

Acknowledgments:

This work was supported by a specially promoted research (1900210) of Grant-in-Aid for Scientific Research from the MEXT, Japan. The authors are grateful to Y. Yoshida, H. Mori, and A. Takaoka for suggestions and discussions, and A. V. Rode and E. G. Gamaly for useful discussions. We acknowledge the UK's Materials Chemistry Consortium for providing HECToR computer resources (EPSRC grant: EP/F067496) and the UCL Legion High Performance Computing Facility, and associated support services. SD is funded by EPSRC under the M3S IDTC and CCFE.